SLAM - Struggling to get to FC shock level

[stevenbrown630]

Howdy TFP,

I've been trying to get my pool to Shock level for the past 36 hours with little success. The pool math app keeps advising to add 2 gallons of 10% chlorine every time I test but I can't seem to get above ~2 FC. I'll even test 15 minutes after adding to see if I get a quick spike but get similar FC readings each time. Should I double or triple down (4-6 gallons or more?) during each addition? Or just stick the course and keep dumping the chlorine until I get up to shock level?

The good news is the pool is no longer green and relatively clear except for after a brush and vacum, although clears up again shortly after that process.

I just can't seem to get up to shock level. Any advice?

I've been logging everything to pool math (sharing from user profile) for the past week or so.

 

[AK-]

Any advice?

Yes, keep going. If you FC is getting down fast it is because it is being "used up" killing what ever is in your water and as you said the water is getting better, so keep trying to get you FC to stay at SLAM level. Perhaps even add LC more frequently. Eventually FC will hold.

 

[AK-]

BTW, in NM you are unlikely to need to winterize your pool, so keep it chlorinated during winter. It is probably going to take less FC to keep the water clear than to do such a big SLAM.

 

[setsailsoon]

Steven,

Welcome to TFP! Sounds like you have a severe algae bloom. The fact that you are seeing color improvement indicates you are oxidizing a LOT of algae. If it was me I'd just add and test more frequently. You don't want to exceed SLAM level which is 12 FC for your CYA level. If you get impatient and want to add an extra gallon check carefully after every addition so don't accidentally go above SLAM. Eventually you will start to oxidize algae quicker than they multiply and then your FC level will increase quickly. But it won't hold too long. Be sure you complete the SLAM and pass all the tests. Failure to do this will just cause a reinfection to emerge again soon.

Chris

 

[MITBeta]

Are you sure that you are using good bleach?

 

[stevenbrown630]

BTW, in NM you are unlikely to need to winterize your pool, so keep it chlorinated during winter. It is probably going to take less FC to keep the water clear than to do such a big SLAM.

I hadn’t considered that but it would make life easier every year.

We do get down to 30-40’s at night with a couple of snows a year here in the high desert (5k ft elevation). Would you still recommend recommend keeping open year round?

 

[stevenbrown630]

Are you sure that you are using good bleach?

I’m pretty sure. The jugs are all from 2022.

 

[AK-]

I hadn’t considered that but it would make life easier every year.

We do get down to 30-40’s at night with a couple of snows a year here in the high desert (5k ft elevation). Would you still recommend recommend keeping open year round?

No. If you get below freezing then your pipes/equipment may not survive the winter with water in it. Sorry I didn’t realize it would get that cold there.

The usual recommendation is to close at SLAM level when water temp gets below 60F and open slightly before it gets above 60F. Chlorine lasts longer in the water below 60F and algae grows really slow in cold temperatures. Here is NJ I close mid-October and open mid-April to a clean pool with some residual chlorine (of course each pool is unique, so results are not guaranteed).